Electric relay



March 29, 1960 o. w. SHIRLEY 2,930,869

ELECTRIC RELAY Filed March 31, 1958 40 Gauss f0 Gauss United. States Patent O M ELECTRIC RELAY Orie W. Shirley, Portland, reg., assignor to Iron Fireman Manufacturing Company, a corporation of Oregon Application March 31, 1958, Serial No. 724,978

Claims. (Cl. 200-87) This invention relates generally to electric relays and more particularly to extremely small or sub-miniature relays.

It is a principal object of this invention to provide an electric relay having an electric switch encapsulated and hermetically sealed in a nonmagnetic metal case of subminiature size in such a manner that the switch can be operated efiiciently by the passage of a magnetic field through the switch transversely of the case.

It is a second object to provide such a switch which will be operated repeatedly and reliably when subjected to an oscillating magnetic field having a flux density of the order of 40 gausses.

It is a third object to provide such a switch which will withstand on each of the three mutually perpendicular axes an acceleration force of at least ten times gravity over a range of 20 to 2000 cycles per second.

It is a fourth object to provide such a switch including no organic materials in its make up and stable in dimensions whereby the switch will operate safely and reliably as desired over a temperature range of 65 C. to +125 C.

It is a fifth object to provide such a switch having operating stability and reliability at any altitude.

It is a sixth object to provide such a switch which will withstand a total of thirty impact shocks of 100 times gravity for about eleven milliseconds along each of three mutually perpendicular axes without damage to the switch.

It is a seventh object to provide a miniature electromagnetic clip into which the switch may be clipped to form a relay.

How these and other objects are attained is disclosed by the following description referring to the attached drawing in which Fig. 1 is a view in end elevation of a preferred form of the relay of this invention.

Fig. 2 is a view inside sectional elevation as seen from the line 22 of Fig. 1.

Fig. 3 is a fragmental view in end sectional elevation as seen from the line 33 of Fig. 2.

Fig. 4 is a bottom plan view as seen from line 4-4 of Fig. 2.

Fig. 5 shows a one inch dimension to the approximate scale to which the details of Figs. 1 to 4 are shown although it is understood that for clarity of disclosure there is some exaggeration of the dimensions of parts in Figs. 1 to 4.

Like numerals of reference refer to like parts in the several figures of the drawing.

Referring now to the drawing there is shown a silver alloy enclosing cover 11 forming part of the complete electric switch 12 of this invention. In the completely assembled and hermetically sealed form of switch 12, cover 11 is fused to non-magnetic metal base cup 13 having a pair of holes 14 and 15 formed through the bottom thereof. Base cup 13 is preferably gold plated.

2,930,869 Patented Mar. 29, 1960 Extending from the outside of switch 12 to the interior thereof through holes 14, 15, as shown are conducting terminals 16, 17, 18 each of about eighteen mils diameter, made of magnetic nickel iron alloy and gold plated. Within cup 13 terminals 16, 17 and 18 are formed as shown and secured in position in base cup 13 by glass insulation 19 placed while molten.

Combined relay armature, moving switch blade and movable switch contact 20 is formed of a round rod of copper nickel iron permanent magnet metal alloy like Cunife made by the Indiana Steel Products Co., Valparaiso, Indiana. Rod 20 is formed with a 19 mil diameter hole transversely therethrough at its center of gravity and is journalled on the inner end of terminal 16 as shown for free and balanced oscillation thereabout. Rod 20 is preferably gold plated. Rod 20 is secured against excessive endplay along the inner end of terminal 16 by its bearing against the insulating upper extension 21 of glass 19 and the insulating retainer 22 secured to the inner end of terminal 16.

The inner ends 17A and 18A of terminals 17 and 18 are seen to be flattened to a thickness of about eight mils and oppositely arced loosely to surround partially one end of rod 20 as shown andthus to form spaced stationary contacts to cooperate with movable contact 20 to comprise a single pole double throw switch having common terminal 16 and alternate throw terminals 17 and 18. The flattening of ends 17A and 18A of terminals 17 and 18 adds to their rigidity to prevent their deformation under the vibratory contact thereof by rod 20.

It should be noted that since terminal wires 16, 17 and 18 are of magnetizable material and since rod 20 is a permanent magnet, the end of rod 20 adjacent ends 17A and 18A of terminal 17 and 18 will normally move toward 17A or 18A whichever is nearest and will tend to adhere to the one toward which it moves to contact. This is a novel and most useful stabilizing phenomenon produced by the use of a permanent magnet as a combined armature and movable contact arm when combined with magnetizable stationary contacts. This results in the substantial elimination of contact bounce and destructive arcing at the contacts.

For operation of the switch 12, it is required that the switch be positioned as shown in Fig. 1 in a magnetic cross field of at least about 40 gausses intensity in which case the north end of the permanent magnet armature 20 will be urged by the magnetic field to move in the direction of north to south intensity drop in the field and the south end of armature 20 will be urged to move in the direction of south to north intensity change of the magnetic field and armature 20 will rotate to contact the appropriate one of the stationary contacts 17A, 18A.

It will of course be understood by a worker in the art that the switch operation will be controlled as desired by use of a magnetic field varying in amplitude with time as desired. For instance if intermittent or aperiodic operation of the switch is desired, the armature 20 may be mechanically biased toward contact with one of the contacts 17A or 18A and a unidirectional magnetic field can be aperiodically applied to overcome the bias and operate the switch as desired.

However if it is desired that the switch be operated periodically to alternate throw positions it is only necessary to apply a magnetic field of the required frequency of alternation.

Only as an example of how the switch 12 can be associated with an alternating magnetic field to provide an electromagnetically operated relay having a desired periodicity of switch operation, there is shown in Figs. 1, 2 and 3 a magnetizable metal strap about one fourth inch wide and ten mils thick bent into a supporting clip aaeqeee 23 for switch 12. A few turns of insulated wire 24 as required by the excitation circuit to be attached to ends 25, 26 of wire 24 are wound about clip 23 as shown. The cross magnetic field between pole pieces 27, 28, will follow the excitation current circulating in coil 24 due to the electrical character of the circuit attached to terminals 25 and 26 and with the impressed frequency of current alternation. When the impressed current rises to a preset value the moving contact 20 of switch 12 will move from one of the throw contacts 17A or 18A to the other and thus alternate in throw position in response to the alternating current in coil 24.

Having listed some of the objects of my invention, illustrated and described a preferred form in which my invention may be practiced and explained its operation, I claim: a

1. An electric switch hermetically sealed in a nonmagnetic case and operable in response to selected Values ofa magnetic field impressed transversely thereon through said case, said switch comprising an insulating base, a

plurality of switch terminals supported on said base to extend from at least one side thereof, a permanent magnet moving contact blade rotatably carried on one ofsaid terminals on said side of said base for rotation about the center of gravity of said blade, another of said switch terminals on said side of said base terminating in a magnetic end forming a stationary contact for said switch, a stop for said blade supported on said base and spaced from said other of said terminals, said other terminal and said stop being positioned to limit the rotation of said contact blade in the respective two directions thereof.

2. An electric switch comprising an insulating base, a plurality of switch terminals supported on said base to extend from one side thereof, a permanent magnet moving contact blade formed with a bearing hole transversely therethrough at its center of gravity, one end of said blade at one side of said hole having one magnetic polarity and the other end of said blade at the other side of said hole having the other magnetic polarity, one of said switch terminals extending from said base on said one side forming a journal for said blade at said hole freely to carry said blade for rotation about said terminal journal, another of said switch terminals on said side of said base terminating in a magnetic end forming a stationary contact for said switch, a stop for said blade supported on said base and spaced from said other of said terminals, said other terminal and said stop being positioned to limit the rotation of said contact blade in the respective two directions thereof.

3. The switch of claim 2 in which said stop is a third one of said plurality of switch terminals on said side of said base and terminates in a magnetic end forming another stationary contact for said switch.

4. The switch of claim 2 including a non-magnetic hermetically sealed cover therefor.

5. The switch of claim 3 in which said glass base forms part of said cover and said plurality of switch terminals extend outside said cover from the other side of said base.

References Cited in the tile of this patent UNiT ED STATES PATENTS 1,949,994 Dkytor et al. Mar. 6, 1934 2,037,535 Rankin Apr. 14, 1936 2,253,856 Harrison Aug. 26, 1941 2,635,155 Barr Apr. 14, 1953 2,706,756 Brewer Apr. 19, 1955 2,767,279 Hall Oct. 16, 1956 2,866,870 Smiley Dec. 30, 1958 2,872,546 Babcock Feb. 3, 1959 

